1. Field of the Invention
The present invention relates to an illumination system. More particularly, the present invention relates to an illumination system suitable for applying to a projection apparatus.
2. Description of Related Art
Referring to FIG. 1, the conventional illumination system 100 is composed of a first light-collecting module 110, a second light-collecting module 120, and a dichroic mirror 130. The first light-collecting module 110 is composed of a light source 112, a rod integrator 114, and a lens 116, and the second light-collecting module 120 is composed of a light source 122, a rod integrator 124, and a lens 126. The light source 112 is suitable for emitting a first color light 113, wherein the first color light 113 transmits to the dichroic mirror 130 after passing through the rod integrator 114 and the lens 116. The light source 122 is suitable for emitting a second color light 123, wherein the second color light 123 transmits to the dichroic mirror 130 after passing through the rod integrator 124 and the lens 126. The dichroic mirror 130 passes the first color light 113 and reflects the second color light 123 so that the first color light 113 can be integrated with the second color light 123.
The light-collecting modules 110 and 120 take up a lot of space for they are composed of many components. Accordingly, the volume of the illumination system 100 is very large. Besides, in such a design, the refractivity and reflectivity of the dichroic mirror 130 vary with the light incident angle, thus, the uniformities of the first color light 113 and the second color light 123 through the dichroic mirror 130 are different. Accordingly, an image projected by a projection apparatus using the conventional illumination system 100 may has the problem of poor uniformity.